Novel tetrasubstituted bicyclic amide acetals and process for their manufacture

ABSTRACT

Novel bicyclic amide acetals having substituents in the 2, 5 and 7 positions and a process for their preparation are described.

This invention relates to novel substituted bicyclic amide acetals andmore particularly pertains to 2, 2, 5, 7 tetra-substituted bicyclicamide acetals and to the process for their preparation.

The bicyclic amide acetals have the general formula I: ##STR1##

Although unsubstituted, mono-, Di- and tri-substituted bicyclic amideacetals of formula I with substituents at the 3, 5 and 7 positions areknown (Synthesis 16, 1971), no bicyclic amide acetals with substituentsat the 2, 5 and 7 positions were known prior to the time of myinvention.

Bicyclic amide acetals, per se, and those with substituents at the 3, 5and 7 positions are known to react with water, and reactive hydrogencompounds such as alcohols, phenols, carboxylic acids, etc. The bicyclicamide acetals of my invention will react with water but not withphenols, carboxylic acids, etc., which makes them excellent moisturescavengers even in the presence of reactive hydrogen compounds and thisproperty is, indeed, unexpected in view of the prior art.

The novel compositions of my invention are those conforming to thegeneral formula II: ##STR2##

In Formula II, R represents a hydrocarbon group and preferably an alkylgroup having from 1 to 10 carbon atoms, R' represents a hydrocarbongroup and preferably an alkyl group having from 1 to 20 carbon atoms oran aryl group having from 6 to 10 carbon atoms, and R" represents ahydrocarbon or ether group, and preferably an alkyl, aralkyl, alkylether or aralkyl ether group having from 1 to 20 carbon atoms. Thesynthesis of the bicyclic amide acetals of my invention involves thereaction of an oxazoline (III) with an epoxide (IV) as shown in thefollowing equation: ##STR3## Wherein R, R' and R" have the foregoingdesignations. The reaction is carried out at a temperature in the rangeof from 100° to 220° C. and preferably in the range of from 140°-200° C.in a dry inert atmosphere at atmospheric or near atmospheric pressure.The synthesis is advantageously carried out in the presence of a smallamount (less than 5% by weight) of catalyst which can be an alkali metalor alkaline earth metal or salt thereof.

The following examples will further illustrate this invention.

EXAMPLE 1

A mixture of 30 g of 2, 4, 4-trimethyl-2-oxazoline and 39.8 g of 1,2-epoxy-3-phenoxy propane was placed in a glass reactor equipped with amagnetic stirrer, thermometer, condenser and dry nitrogen inlet. To themixture was added 0.1 g of LiCl and the reaction was carried out at150°-160° C. with stirring and under a dry nitrogen atmosphere for about6 hours. GLC analysis showed that more than 95% of the startingoxazoline and epoxide had reacted to give the bicyclic amide acetal (IIin which R and R' are methyl and R" is --CH₂ O Ph). The product wasfractionally distilled under reduced pressure (115° C. at 0.1 mm Hg) togive a clear, colorless liquid in about 85% yield.

EXAMPLE 2

The procedure of Example 1 was followed except that 37.8 g of theoxazoline and 38 g of allyl glycidal ether were used. The reaction wascarried out at 150° C. for 81/2 hours during which time more than 70% ofthe starting materials reacted to form the bicyclic amide acetal (II inwhich R and R' are methyl and R" is --CH₂ O CH═CH₂) which wasfractionally distilled at 62° C./0.05 mm Hg as a colorless liquid inabout 60% yield.

EXAMPLE 3

The procedure of Example 2 was followed using 50.6 g of2-undecyl-4,4-dimethyl-2-oxazoline and 23 g of the allyl glycidal ether.After 8 hours of reaction at 160° C., GLC analysis indicated that about85% of the starting materials had reacted. The bicyclic amide acetalproduct (II in which R is methyl, R' is --C₁₁ H₂₃ and R" is --CH₂ O--CH₂--CH═CH₂) was distilled at 125° C./0.1 mm Hg in about 75% yield.

EXAMPLE 4

This Example illustrates the reation of the bicyclic amide acetals of myinvention with water. The bicyclic amide acetal prepared in Example 2(1.24 g) was allowed to react with 0.1 g of water at room temperature(constant temperature bath held at 24° C.) and GLC analysis showed thatcomplete hydrolysis had taken place in about 40 minutes.

EXAMPLE 5

This Example illustrates that the bicyclic amide acetals of thisinvention do not react with carboxylic acids. The bicyclic amide acetalof Example 2 (2.249) and hexanoic acid (1.29) were mixed at roomtemperature under a dry nitrogen atmosphere. The reaction mixture wasstirred at room temperature for 2 hours and a portion was silylated witha silylating agent, bis-trimethylsilyl trifluoride acetamide (BSTFA) andanalyzed by GLC. The silylating agent is used to inactivate thecarboxylic acid to prevent interference in the GLC analysis. This testshowed that essentially all of the starting material, both acid andacetal, was still present and that no new material had been formed. Theremaining reaction mixture was heated at 60° C. for 5 hours and againanalysis of the resulting reaction mixture showed that no reaction hadtaken place between the carboxylic acid and the substituted bicyclicamide acetal of this invention.

EXAMPLE 6

This experiment which is outside the scope of the present inventiondemonstrates that substituted bicyclic amide acetals of the prior art doreact readily with carboxylic acids. A disubstituted bicyclic amideacetal (II in which R is H, R' is CH₃ CH₂ -- and R" is --CH₂ OCH₂CH═CH₂) (2.1 g) and 1.2 g of hexanoic acid were allowed to react at 60°C. for 30 minutes and at the end of this time GLC analysis of thereaction mixture showed complete reaction of the starting materials togive the ester-amide-ol product (HO--CH₂ --CH₂ --N(COET)CH₂ CH(CH₂ OCH₂CH═CH₂)OCOC₅ H₁₁).

EXAMPLE 7

A. This demonstrates that the substituted bicyclic amide acetals of thisinvention do not react with phenols. A bicyclic amide acetal (of FormulaII in which R is --CH₃, R' is --CH₃ and R" is --CH₂ OCH₂ CH═CH₂) (2.2 g)and 0.95 g of phenol were heated at 130° C. under nitrogen for 2 hoursand analyzed by GLC. Only the starting materials were found to bepresent.

B. A repeat of A of this Example using the prior art bicyclic amideacetal (Formula II in which R is H, R' is Et, and R" is --CH₂ OCH₂CH═CH₂). In 50 minutes essentially complete reaction of the bicyclicamide acetal and phenol had occurred as determined by GLC analysis.

EXAMPLE 8

This Example illustrates that the tetrasubstituted bicyclic amideacetals of this invention are useful water scavenging agents in thepresence of carboxylic acids.

To a mixture of 1.7 g of methacrylic acid and 0.37 g of water was added4.5 g of tetrasubstituted bicyclic amide acetal (Formula II, R is Me, R'is Me, and R" is --CH₂ OCH₂ CH═CH₂) at room temperature. An exothermicreaction resulted. GLC analysis (after silylation) showed that withintwo minutes essentially all of the starting tetrasubstituted bicyclicamide acetal had reacted to give the hydrolysis product and that thestarting methacrylic acid remained. This indicated that the amideacetals of this invention are selective dehydrating agents and that thehydration reaction is acid catalyzed.

EXAMPLE 9

This demonstrates selective moisture scavenging ability of thetetrasubstituted bicyclic amide acetals of this invention in thepresence of phenols.

To a mixture of 2 g of phenol and 0.35 g of water was added 4.6 g of atetrasubstituted bicyclic amide acetal of Formula II in which R is Me,R' is Me, and R" is --CH₂ OPh. The reaction mixture was stirred at roomtemperature for 5 minutes and was then analyzed by GLC which showed thecomplete conversion of the bicyclic amide acetal to the correspondinghydrolyzed product and that the phenol remained unreacted.

I claim:
 1. The composition conforming to the Formula ##STR4## wherein Rrepresents an Alkyl group having from 1 to 10 Carbon Atoms, R'represents an Alkyl group having from 1 to 20 Carbon Atoms or an Arylgroup having from 6 to 12 Carbon Atoms and R" represents A memberselected from the group consisting of --CH₂ OC₆ H₅ and --CH₂ OCH₂CH═CH₂.
 2. The composition of claim 2 wherein R and R' are methyl groupsand R" is --CH₂ OC₆ H₅.
 3. The composition of claim 2 wherein R and R'are methyl groups and R" is CH₂ OCH₂ CH═CH₂.
 4. The composition of claim2 wherein R is a methyl group, R' is C₁₁ H₂₃ and R" is CH₂ OCH₂ CH═CH₂.